Members Geocoder Question.

I have imported my members into my new site and their address has been successfully imported into the ‘Location’ xprofile field. However they only show up on the map if they actuall go to their profile page and click update. I thought the Member Geocoder was able to do this behind the scene in batches? I try it and it giver the error:
There was nothing to geocode in this batch. Please try another batch.

Any help would be greatly appreciated.